It depends on how far you wish to go as to what needs replacing. If you are going k04 and a stage 1 map then nothing apart from the turbo, dv relocation would need changing. However if you want more power you will need a hpfp internal upgrade, an intake, poss intercooler, injectors, full tbe exhaust, larger brakes and uprated suspension. Id do the brakes and suspension mods first though. Although id perhaps stick with a stage 1 map k04 as that will get you around 300bhp which is more than enough for a fwd car and wont cost the earth to do. Id stick with the oe intake as the aftermarket intakes do give good bhp high in the rev range but you do lose low end torque, which means having to rev the engine harder round town to get going. I switched back to the oe intake and found my car drove much nicer with every day driving.
